Basin ecological security is a major issue for human survival and development and has become an important branch in the field of social security research. This paper applies the principles and analytical methods of landscape ecology to evaluate the ecological security of the Chahannaoer Basin. Starting from the perspective of landscape structure, the ecological security status of the basin in 2010 and 2024 was evaluated using metrics such as Patch Density (PD), Landscape Shape Index (LSI), Landscape Division Index (DIVISION), and Landscape Aggregation Index (AI). Furthermore, a dynamic change analysis is conducted. Meanwhile, the study calculated the intensity of mutual transitions between ecosystem types and the overall dynamic degree of the watershed within the specified time period. The results indicate that between 2010 and 2024, the forest area and construction land in the basin showed an upward trend, while the grassland area showed a downward trend, and the saline-alkali land area increased significantly. A comprehensive analysis of the spatial distribution patterns of the indices PD, LSI, DIVISION, and AI reveals that the fragmentation of most landscapes decreased. Notably, the fragmentation of croplands and forests showed a significant decline, whereas the fragmentation of wetlands increased sharply. During this period, the land cover transition index and the comprehensive land cover change rate in the Chahannaoer Basin were 47.36% and 20.54%, respectively, indicating that land cover types are still transitioning towards a more favorable state.